The invention relates to a method and system for robot localization and confinement.
There have been many systems proposed in the prior art for confining a robot to specific physical space for the purpose of performing work. These systems are typically designed for any number of robotic applications such as lawn care, floor cleaning, inspection, transportation, and entertainment, where it is desired to have a robot operate in a confined area for performing work over time.
By way of example, a vacuuming robot working in one room may unintentionally wander from one room to another room before satisfactorily completing the vacuuming of the first room. One solution is to confine the robot to the first room by closing all doors and physically preventing the robot from leaving the first room. In many houses, however, open passageways often separate rooms, and doors or other physical barriers cannot easily be placed in the robot's exit path. Likewise, a user may desire to only have the robot operate in a portion of a single open space and, therefore, letting the robot work in the entire room decreases efficiency.
It is therefore advantageous to have a means for confining the area in which a robot works.
One approach in the prior art is to provide sophisticated systems for navigation and orientation for the robot such that the robot either travels along a predetermined path and/or monitors its current location against a map stored in memory. These systems require sophisticated hardware, such as precision sensors and significant computer memory and computational power, and typically do not adapt well to changes in the area in which the robot is working. Likewise the robot cannot simply be taken from one building to another building, or even from room-to-room, without significant reprogramming or training.
For example, the method disclosed in U.S. Pat. No. 4,700,427 (Knepper) requires a means for generating a path for the robot to travel, which can be either a manually-controlled teaching of the path or automatic mapping function. If “the place of use is frequently changed” or the “rooms are modified,” large amounts of data memory is required in order to store information related to each location. Similarly, the method and system disclosed in U.S. Pat. No. 4,119,900 (Kremnitz) requires powerful computation and sensors to constantly ascertain the orientation of the robot in a given space. Other examples of robotic systems requiring inputted information about the space in which the robot is working include methods and systems shown in U.S. Pat. No. 5,109,566 (Kobayashi et al.) and U.S. Pat. No. 5,284,522 (Kobayashi et al.).
Similarly, certain prior art systems not only require the training or programming of the robot to the specifics of a particular space, but also require some preparation or alteration to the space in which the robot is to work. For example, U.S. Pat. No. 5,341,540 (Soupert et al.) discloses a system in which in a preferred embodiment requires the robot to include a positioning system and that the area for the robot be set up with “marking beacons . . . placed at fixed reference points.” While this system can avoid an unknown obstacle and return to its preprogrammed path through signals from the beacons, the system requires both significant user set-up and on-board computational power.
Similar systems and methods containing one or more of the above-described disadvantages are disclosed in U.S. Pat. No. 5,353,224 (Lee et al.), U.S. Pat. No. 5,537,017 (Feiten et al.), U.S. Pat. No. 5,548,511 (Bancroft), and U.S. Pat. No. 5,634,237 (Paranjpe).
Yet another approach for confining a robot to a specified area involves providing a device defining the entire boundary of the area. For example, U.S. Pat. No. 6,300,737 (Bergvall et al.) discloses an electronic bordering system in which a cable is placed on or under the ground to separate the inner area from the outer area. Likewise, the system disclosed in U.S. Pat. No. 6,255,793 (Peless et al.) requires installation of a metallic wire through which electricity flows to define a border. While these systems provide an effective means for confinement, they are difficult to install, are not portable from room-to-room, and can be unsightly or a tripping hazard if not placed under ground or beneath carpeting. Equally important, such systems can be difficult to repair if the wire or other confinement device breaks, as the location of such breaks can be difficult to determine when the system is placed underground or under carpet.
The present invention provides a modified and improved system for confining a robot to a given space without the drawbacks of the prior art.